"Another option with the Wireless Intellimouse Explorer you'll see is the "Power Saving Feature" it provides. According to Microsoft, this is a breakthrough power saving technology that conserves battery life by using "Intelligent Touch" which engages the optical technology when you touch the mouse, and also puts the mouse into "sleep" mode when you remove your hand. This is also a feature that I'm unsure of which MS has yet to fully optimize for current use. Many times I found the wireless mouse unresponsive for a fraction of time before it would move. Almost to be expected given the use of batteries, yet unacceptable in many situations. It was a minor annoyance that turned into an outright hassle after a short period of time. Something that may improve in newer releases of both hardware and software, but currently remains quite aggravating. "